Compact Adaptively Secure ABE from k-Lin: Beyond NC1 and Towards NL
Compact Adaptively Secure ABE from k-Lin: Beyond NC1 and Towards NL
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DOI:
10.1007/978-3-030-45727-3_9
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发表时间:
2020-05
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通讯作者:
Huijia Lin;Ji Luo
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文献类型:
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作者:
Huijia Lin;Ji Luo
We present a new general framework for constructingcompactandadaptively secureattribute-based encryption (ABE) schemes fromk-Lin in asymmetric bilinear pairing groups. Previously, the only construction [Kowalczyk and Wee, Eurocrypt ’19] that simultaneously achieves compactness and adaptive security from static assumptions supports policies represented byBoolean formulae. Our framework enables supporting more expressive policies represented byarithmetic branching programs.Our framework extends to ABE for policies represented by uniform models of computation such as Turing machines. Such policies enjoy the feature of being applicable to attributes of arbitrary lengths. We obtain the first compact adaptively secure ABE for deterministic and non-deterministic finite automata (DFA and NFA) fromk-Lin, previously unknown from any static assumptions. Beyond finite automata, we obtain the first ABE for large classes of uniform computation, captured by deterministic and non-deterministiclogspaceTuring machines (the complexity classesand) based onk-Lin. Our ABE scheme has compact secret keys of size linear in the description size of the Turing machineM. The ciphertext size grows linearly in the input length, but also linearly in the time complexity, and exponentially in the space complexity. Irrespective of compactness, we stress that our scheme is the first that supports large classes of Turing machines based solely on standard assumptions. In comparison, previous ABE for general Turing machines all rely on strong primitives related to indistinguishability obfuscation.